#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2018 crane <crane@his-pc>
#
# Distributed under terms of the MIT license.

"""

"""


class Solution:
    def convertToRPN(self, expression):
        pass


def main():
    print("start main")

if __name__ == "__main__":
    main()
